1. Field of the Invention
The present invention relates to a titanium powder production apparatus and method and, more particularly, to such an apparatus and method that prevents contamination of the titanium powder.
2. Description of the Background Art
Powder metallurgy is an important technology in the production of parts made out of titanium for critical applications such as aerospace. Titanium metal powder is the basic raw material in this process path. Atomization using an inert gas such as argon is a commonly used process to produce uniform spherical-shaped powders that possess high packing densities. A typical device for gas atomization consists of a liquid metal stream supply source, the atomizing gas jet, and a cooling chamber. The free-falling stream of molten titanium is impinged with inert gas jet at a high velocity, the atomized droplets of titanium solidify in flight through the chamber, and are collected at the bottom of the chamber. Extremely high values of cooling rates during the solidification of the droplets are desired in order to obtain very specific, controlled structures. Several aspects of design and construction of the atomization chamber are important:                1. The chamber must be constructed with a material that does not react with titanium up on contact;        2. The chamber must be large enough to allow titanium droplets to solidify before they come in contact with the walls or bottom section of the chamber;        3. The chamber should allow complete evacuation to prevent atmospheric contamination; and        4. The chamber design should allow easy access for complete cleaning and inspection of its interior.        
Stainless steel is the most commonly used material for the construction of titanium atomization chambers. There exists a possibility that some of titanium droplets hit the atomization chamber before solidification. These droplets react with stainless steel producing low-melting point compounds that are brittle in nature. These compounds enter into the titanium powder stream as contaminants and remain undetected in standard quality control techniques. Components made out of these contaminated powders experience catastrophic in-service failures.